1. Field of the Invention
The present invention relates to paper-making machines, and, more particularly, to a roll within a paper-making machine and method of manufacturing the same.
2. Description of the Related Art
A paper-making machine receives a prepared fiber suspension and produces a fiber web, such as a paper web. The paper-making machine typically includes a plurality of rolls along the length thereof which respectively carry a plurality of traveling substrates through the paper-making machine. For example, each respective roll may carry a forming fabric, belt, felt and/or fiber web (such as a paper web). Depending upon the intended use of the roll, the roll configuration varies from one roll to another within a paper-making machine. For example, a roll may be constructed from granite which is very heavy and has good release properties. Such a roll may weigh 20 tons or more, and may rotate with a tangential speed of about 3500 feet per minute. With such a heavy mass and high rotational speed, the inertia of this type of roll is very high.
For other applications, it is desirable to maintain the inertia of the rotating roll relatively low. For example, a roll within a paper-making machine may be used to measure tension on a traveling substrate carried thereby. Typically, load cells are associated with the bearing journal at each end of the rotating roll which provide output signals indicative of the tension within the traveling substrate. It is desirable to maintain the inertia of such a roll as low as possible to avoid affecting the loads sensed by the load cells.
What is needed in the art is a roll for use in a paper-making machine which has a low inertia, as well as good wear and release properties.
The present invention provides a roll for use in a paper-making machine having an outer surface with different exposed materials to provide optimal wear and release properties.
The invention comprises, in one form thereof, a paper-making machine including a traveling substrate and a roll carrying the substrate. The roll includes a carbon fiber shell, a ceramic layer over the shell, and a polytetrafluoroethylene (PTFE) layer over the ceramic layer. The PTFE layer defines an outer surface of the roll. The ceramic layer intermittently extends through the PTFE layer to the outer surface of the roll.
An advantage of the present invention is that a roll has good wear as well as release properties.
Another advantage is that the wear and release properties may be varied.
Yet another advantage is that the roll may be manufactured using conventional processing techniques, combined together in a novel manner including operating parameters.